Merge pull request #706 from wado-lang/claude/fix-gale-sqlite-parser-SAt2C

Add prediction engine and non-greedy repeat support to parser generator

Author: gfx

docs/cheatsheet.md

@@ -958,6 +958,7 @@ unreachable();            // trap
 
 // core:cli
 use { println, eprintln, print, eprint, Stdout, Stderr } from "core:cli";
+use { log_stdout, log_stderr } from "core:cli";  // no effect required (debug only)
 
 // core:collections - TreeMap, TreeSet
 use { TreeMap, TreeSet } from "core:collections";
@@ -1087,6 +1088,17 @@ let icon = #include_bytes("./icon.png");   // include file as Array<u8>
 
 Paths in `#include_str` and `#include_bytes` are resolved relative to the source file. See [WEP: Compile-Time File Inclusion](./wep-2026-03-02-include-str.md).
 
+## Debugging
+
+```wado
+use { log_stdout, log_stderr } from "core:cli";
+
+log_stdout(`value = {x}`);   // prints to stdout without Stdout effect
+log_stderr(`value = {x}`);   // prints to stderr without Stderr effect
+```
+
+`log_stdout` and `log_stderr` bypass the effect system. They are intended for temporary debugging output that can be called from any function regardless of its effect declarations.
+
 ## Attributes
 
 ```wado

package-gale/AGENTS.md

@@ -97,6 +97,10 @@ Commit the updated golden files.
 
 `runtime.wado` is included verbatim into every generated file via `#include_str` in `generator.wado`. It must remain self-contained (no imports from other source files). See [WEP: Compile-Time File Inclusion](../docs/wep-2026-03-02-include-str.md).
 
+## Generated Parser Rules
+
+- **No backtracking in new code.** Use static k-token lookahead prediction to disambiguate alternatives. If prediction cannot resolve within depth 5, file an issue rather than adding backtracking. Existing backtracking sites are being migrated to prediction; do not add new ones.
+
 ## On-Task-Done
 
 When completing a task, run from the project root:

package-gale/src/g4/parser.wado

@@ -180,26 +180,32 @@ impl G4Parser {
     fn parse_postfix(&mut self, elem: Element) -> Result<Element, ParseError> {
         if self.is_kind(G4Token::Star) {
             self.advance();
-            if self.is_kind(G4Token::Question) {
+            let ng = if self.is_kind(G4Token::Question) {
                 self.advance();
-            }
+                true
+            } else {
+                false
+            };
             return Result::<Element, ParseError>::Ok(
-                Element::Repeat(RepeatElement { kind: RepeatKind::Star, element: elem }),
+                Element::Repeat(RepeatElement { kind: RepeatKind::Star, element: elem, non_greedy: ng }),
             );
         }
         if self.is_kind(G4Token::Plus) {
             self.advance();
-            if self.is_kind(G4Token::Question) {
+            let ng = if self.is_kind(G4Token::Question) {
                 self.advance();
-            }
+                true
+            } else {
+                false
+            };
             return Result::<Element, ParseError>::Ok(
-                Element::Repeat(RepeatElement { kind: RepeatKind::Plus, element: elem }),
+                Element::Repeat(RepeatElement { kind: RepeatKind::Plus, element: elem, non_greedy: ng }),
             );
         }
         if self.is_kind(G4Token::Question) {
             self.advance();
             return Result::<Element, ParseError>::Ok(
-                Element::Repeat(RepeatElement { kind: RepeatKind::Optional, element: elem }),
+                Element::Repeat(RepeatElement { kind: RepeatKind::Optional, element: elem, non_greedy: false }),
             );
         }
         return Result::<Element, ParseError>::Ok(elem);

package-gale/src/generator_test.wado

@@ -141,10 +141,12 @@ test "generate repeat fields" {
                             Element::Repeat(RepeatElement {
                                 kind: RepeatKind::Star,
                                 element: Element::RuleRef("item"),
+                                non_greedy: false,
                             }),
                             Element::Repeat(RepeatElement {
                                 kind: RepeatKind::Optional,
                                 element: Element::TokenRef("COMMA"),
+                                non_greedy: false,
                             }),
                         ],
                     },

package-gale/src/ir.wado

@@ -30,6 +30,7 @@ pub variant Element {
 pub struct RepeatElement {
     pub kind: RepeatKind,
     pub element: Element,
+    pub non_greedy: bool,
 }
 
 pub struct LabelElement {

package-gale/src/ir_test.wado

@@ -39,6 +39,7 @@ test "Element variants" {
     let repeat = Element::Repeat(RepeatElement {
         kind: RepeatKind::Star,
         element: Element::TokenRef("INT"),
+        non_greedy: false,
     });
     let label = Element::Label(LabelElement {
         name: "op",